Sub-assembly mounting system

BACKGROUND OF THE INVENTION

00011. Technical Field

0002The present invention relates to a mounting arrangement for a sub-assembly on a vehicle and more particularly to a mounting arrangement and method for modular components and sub-assemblies such as fuel tank modules across a vehicle frame.

00032. Description of the Problem

0004Trucks are built on frames which serve as foundations for the vehicle's body and as a platform on or to which various components may be mounted or attached. A typical full perimeter frame includes, among other components, two longitudinally extending frame rails. The rails are commonly connected to one another by several latitudinal cross members. The cross members provide lateral and torsional rigidity to the frame assembly. One cross member will typically be positioned to support a truck cab. Components, such as fuel and hydraulic tanks, may be mounted across the frame rails perpendicular to the direction of elongation of the vehicle.

0005Back of cab fuel tank modules are known which are supported across the frame rails as illustrated in <figref idref="DRAWINGS">FIG. 3</figref>. In this design, mounting brackets descend from the bottom of the tank module, which allows for attachment to mounting points on the frame rails. The mounting brackets provide good side-to-side alignment, but do not provide fore/aft positioning or good vertical positioning to allow the introduction of fasteners.

0006Assembly of vehicles would be eased if fuel tank modules were automatically aligned with the correct position on the vehicle chassis for attachment to the chassis as the fuel tank modules were positioned on the vehicle.

SUMMARY OF THE INVENTION

0007The present invention provides a vehicle chassis with a modular sub-assembly such as a tank for fuel or hydraulic fluid. The vehicle chassis has first and second longitudinally aligned frame rails. Each frame rail has an outwardly oriented side. First and second rail side brackets are mounted to the outwardly oriented sides of the first and second frame rails, respectively. Each rail side bracket has a pair of outward extending, parallel guide or alignment arms. The module is supported latitudinally across the frame rails from an elongated carrier forming the bottom of the module. The elongated carrier is supported from below on back edges of the first and second rail side brackets. Four mounting tabs descend from the elongated carrier, extending downwardly from the module. Each mounting tab has a one to one correspondence with a different, alignment arm. The four mounting tabs are spaced to straddle the frame rails to the outside and to bracket the alignment arms as the module is lowered onto the chassis. To effect this cooperation the mounting tabs have alignment edges along one side facing the outside face of the frame rail and leading cam sections along the bottom portion of the mounting tab. The alignment edges urge the module into the correct side-to-side position working against the frame rails and the cam sections urge the module into the correct fore/aft position working against the alignment arms. The module is vertically positioned by the support provided the module from the back edges of the rail side brackets. Fastening points are provided through the guide/alignment arms and mounting tabs.

0008Additional effects, features and advantages will be apparent in the written description that follows.

BRIEF DESCRIPTION OF THE DRAWINGS

0009The novel features believed characteristic of the invention are set forth in the appended claims. The invention itself however, as well as a preferred mode of use, further objects and advantages thereof, will best be understood by reference to the following detailed description of an illustrative embodiment when read in conjunction with the accompanying drawings, wherein:

0010<figref idref="DRAWINGS">FIG. 1</figref> is a perspective view of a vehicle chassis.

0011<figref idref="DRAWINGS">FIG. 2</figref> is a partial view of a pair of frame rails from the vehicle chassis of <figref idref="DRAWINGS">FIG. 1</figref>.

0012<figref idref="DRAWINGS">FIG. 3</figref> is a partially exploded view of a prior art fuel tank module and chassis combination.

0013<figref idref="DRAWINGS">FIG. 4</figref> is a partially exploded view of a modular fuel tank sub-assembly and chassis combination in accordance with one embodiment of the present invention.

0014<figref idref="DRAWINGS">FIG. 5</figref> is a front elevation of the modular fuel tank sub-assembly as positioned on the parallel frame rails of the chassis.

0015<figref idref="DRAWINGS">FIG. 6</figref> is a side elevation of the modular fuel tank sub-assembly.

0016<figref idref="DRAWINGS">FIG. 7</figref> is a perspective view of the modular fuel tank sub-assembly.

0017<figref idref="DRAWINGS">FIG. 8</figref> is a perspective view of the modular fuel tank sub-assembly attached to a vehicle chassis.

DETAILED DESCRIPTION OF THE INVENTION

0018Referring now to the figures and in particular to <figref idref="DRAWINGS">FIG. 1</figref>, a perspective view of a vehicle chassis <b>10</b> is illustrated. The foundational component of chassis <b>10</b> is a box frame <b>12</b>. Frame <b>12</b> provides connection points for suspension elements for numerous vehicle components, including by way of example, rear axle <b>18</b> and front axle <b>19</b>. Rear wheels <b>20</b> and front wheels <b>22</b>, are mounted on axles <b>18</b> and <b>19</b>, respectively. Frame <b>12</b> carries an engine <b>14</b> and dash panel <b>16</b> and provides a base for the construction of a body (not shown) and a place to position the modular tank of the present invention.

0019<figref idref="DRAWINGS">FIG. 2</figref> illustrates that box frame <b>12</b> is constructed in part from two elongated frame rails <b>24</b> and <b>26</b>, each of which run substantially the length of a vehicle and which lie parallel to one another. Frame rails <b>24</b> and <b>26</b> are held parallel to one another by a series of cross members, here arranged perpendicularly to the frame rails, although other orientations for cross members are possible. Among the cross members is an intermediately positioned, cab support cross member <b>30</b>. The cab support cross member <b>30</b> supports a driver and passenger cab positioned on frame <b>12</b>.

0020Frame rails <b>24</b> and <b>26</b> have top and bottom flanges <b>47</b> and <b>45</b>, respectively (visible on frame rail <b>26</b>). Flanges <b>47</b> and <b>45</b> of both rails <b>24</b> and <b>26</b> extend inwardly toward the centerline of the frame <b>12</b>, as illustrated by the flanges from frame rail <b>26</b>. Flanges <b>45</b> and <b>47</b> give frame rails <b>24</b> and <b>26</b> their characteristic C cross sectional shape with flange <b>45</b> providing an upper surface. Numerous holes <b>39</b> pass through frame rails <b>24</b> and <b>26</b> to provide support points for the insertion mounting components such as bolts. Nut and bolt combinations <b>50</b> are illustrated in association with cross member <b>30</b>, providing connection of mounting hardware for the cross member to frame rail <b>24</b>.

0021Referring to <figref idref="DRAWINGS">FIG. 3</figref> a prior art method of installing a fuel tank module <b>40</b> on a pair of frame rails <b>24</b>, <b>26</b> is illustrated. Fuel tank module <b>40</b> comprises a fuel tank <b>42</b> set in an elongated carrier <b>44</b> which may be constructed of support rails <b>60</b> and end plates <b>62</b> to form a rectangular cradle to receive the bottom portion of the fuel tank. Carrier <b>44</b> supports fuel tank <b>42</b> from underneath and provides a frame which may be rested across frame rails <b>24</b> and <b>26</b>. The fuel tank is held in carrier <b>44</b> by straps <b>61</b> which are wrapped across the top of the tank from each side. Extending downwardly from carrier <b>44</b> are two mutually spaced mounting brackets <b>64</b> and <b>66</b>. Mounting brackets <b>64</b>, <b>66</b> are spaced to fit around the relative outside faces of frame rails <b>24</b> and <b>26</b>. The outside faces (including outside face <b>25</b> for frame rail <b>24</b>) are flat faces oriented facing away from the longitudinal centerline of chassis <b>10</b>. Right side mounting bracket <b>66</b> includes a bottom edge <b>68</b> which is turned outwardly relative to frame rail <b>26</b> at the bottom of the bracket to allow some initial side to side play in fit as fuel tank module <b>40</b> is lowered onto a vehicle chassis. The minimum spacing between brackets <b>64</b> and <b>66</b> is however set to much closer tolerances to provide a snug fit for the brackets around frame rails <b>24</b> and <b>26</b>. This provides good side to side positioning of the fuel tank module <b>40</b>, however, it leaves it to the production workers on the line to adjust the front to back and vertical position of the fuel tank module to bring attachment points <b>41</b> on the mounting brackets into alignment with attachment points <b>39</b> in frame rails <b>24</b> and <b>26</b>.

0022Referring now to <figref idref="DRAWINGS">FIG. 4</figref>, a partially exploded view of a vehicle chassis and fuel tank assembly is illustrated with a sub-assembly, here a fuel tank module <b>70</b>, shown above its mounting position across vehicle frame rails <b>24</b> and <b>26</b>. In the present invention, as distinguished from the prior art described with reference to <figref idref="DRAWINGS">FIG. 3</figref>, the mounting hardware is divided between portions installed on frame rails <b>24</b> and <b>26</b> prior to mounting of the fuel tank module <b>70</b>, namely side rail brackets <b>80</b> and <b>82</b>, and those components descending from the fuel tank module, namely four mounting tabs <b>71</b>, <b>72</b>, <b>73</b> and <b>74</b> (with mounting tabs <b>73</b>, <b>74</b> shown in <figref idref="DRAWINGS">FIG. 7</figref>). Side rail brackets <b>80</b> and <b>82</b> are C-channel shaped metal components, attached along back sections <b>97</b> and <b>99</b>, respectively, to the outer faces of frame rails <b>24</b> and <b>26</b>. Conventional fasteners, such as nuts and bolts, may be used to mount side rail brackets <b>80</b>, <b>82</b> from the outer faces of frame rail <b>24</b> and <b>26</b>, with the bolts positioned through mounting hole attachment points <b>39</b> in the frame rails and openings through the back sections <b>97</b>, <b>99</b> of the side rail brackets. Side rail brackets <b>80</b> and <b>82</b> each include two outwardly oriented arms or guide arms, including guide arms <b>86</b> and <b>88</b> from side rail bracket <b>80</b> and guide arms <b>87</b> and <b>89</b> from side rail bracket <b>82</b>. Attachment of fuel tank module <b>70</b> to frame rails <b>24</b>, <b>26</b> is effected by attachment of the four mounting tabs <b>71</b>–<b>74</b> to the guide arms of the two side rail brackets <b>80</b>, <b>82</b>.

0023Rail side brackets <b>80</b>, <b>82</b> cooperate with mounting tabs <b>71</b>–<b>74</b> to provide front to back positioning of fuel tank module <b>70</b>. Rail side brackets <b>80</b>, <b>82</b> further provide a support for elongated carrier <b>44</b> to position fuel tank module <b>70</b> vertically. Rail side brackets <b>80</b> and <b>82</b> are located on frame rails <b>24</b> and <b>26</b> to leave the topmost portions of back sections <b>97</b> and <b>99</b> extending above the upper faces of frame rails. This arrangement positions support edges <b>81</b> and <b>83</b> to support elongated carrier <b>44</b> from its bottom surface, or the bottom surface of its exterior rails <b>60</b>. Guide arms <b>86</b>–<b>89</b> are truncated right triangular shaped projections, with one base providing juncture with the respective back sections of the rail side brackets <b>80</b>, <b>82</b>. Attachment points <b>139</b> are provided through each of the guide arms <b>86</b>–<b>89</b> and attachment points <b>239</b> are provided through mounting tabs <b>71</b>–<b>74</b>. A step <b>101</b> is illustrated extending past one end <b>62</b> of elongated carrier <b>60</b>.

0024Mounting tabs <b>71</b>–<b>74</b> cooperate with frame rails <b>24</b>, <b>26</b> to locate fuel tank module <b>70</b> from side to side over the frame rails. Referring to <figref idref="DRAWINGS">FIG. 5</figref> mounting tabs <b>71</b> and <b>72</b> may be seen to descend from side rail <b>60</b> of elongated carrier <b>44</b>, extending downwardly from the carrier (in its usual orientation) to the relative outside of chassis <b>10</b> as defined by frame rails <b>24</b> and <b>26</b>. Mounting tabs <b>73</b> and <b>74</b>, which do not appear in this figure operate in the same fashion and the discussion relating to tabs <b>71</b> and <b>72</b> is equally applicable to them. Side rail brackets <b>80</b>, <b>82</b> are deleted from <figref idref="DRAWINGS">FIG. 5</figref> to better illustrate the interaction of mounting tabs <b>71</b> and <b>72</b> with frame rails <b>24</b> and <b>26</b>. The relative interior edges <b>171</b> and <b>172</b> of mounting tabs <b>71</b> and <b>72</b>, respectively, are angled away from the outer faces <b>27</b> and <b>25</b> from top to bottom. Interior edges <b>171</b> and <b>172</b> function as cams against the upper edges of outer faces <b>27</b> and <b>25</b> to urge fuel tank assembly <b>70</b> toward a centered position over frame rails <b>26</b> and <b>24</b> as the fuel tank assembly is lowered onto the rails, even if the fuel tank assembly is initially somewhat misaligned relative to the chassis.

0025Referring to <figref idref="DRAWINGS">FIGS. 6 and 7</figref>, the operation of mounting tabs <b>71</b>–<b>74</b> cooperating with guide arms <b>86</b>–<b>89</b> to effect correct positioning of the fuel tank assembly from front to back along chassis <b>10</b> is illustrated. Frame rails <b>24</b> and <b>26</b> are deleted from the drawings for clarity of illustration. Each of mounting tabs <b>71</b>–<b>74</b> corresponds with one of guide arms <b>86</b>–<b>89</b>. The correspondences are as follows: mounting tab <b>71</b> with guide arm <b>87</b>; mounting tab <b>72</b> with guide arm <b>86</b>; mounting tab <b>74</b> with guide arm <b>88</b>; and mounting tab <b>73</b> with guide arm <b>89</b>. When fuel tank assembly <b>70</b> is fully lowered onto frame rails <b>24</b> and <b>26</b>, front to back pairs of mounting tabs snugly bracket to the outside front to back pairs of guide arms. A front to back pair of guide arms are the guide arms extending from a particular side rail bracket. Front to back pair of mounting tabs <b>71</b>, <b>73</b> corresponds to the guide arms of side rail bracket <b>82</b> and front to back pair of mounting tabs <b>72</b>, <b>74</b> corresponds to the guide arms of side rail bracket <b>80</b>.

0026The lower edges of mounting tabs <b>71</b>–<b>74</b> turn outwardly from the corresponding guide arms for each mounting tab, thereby providing lower cam sections <b>171</b>–<b>174</b>. When fuel tank module <b>70</b> is lowered onto rail side brackets <b>80</b> and <b>82</b>, alignment need not be initially perfect. Any of cam sections <b>171</b>–<b>174</b> may impinge against its corresponding guide arm, resulting in the fuel tank module <b>70</b> being urged forward or backward into alignment on the guide arms, assuring alignment of the attachment points on the mounting tabs with attachment points on the guide arms. Alignment of mounting tabs <b>71</b>–<b>74</b> with guide arms <b>86</b>–<b>89</b> may be assured by fixing the side rail brackets <b>80</b> and <b>82</b> when attaching them to frame rails <b>24</b>, <b>26</b>.

0027Referring to <figref idref="DRAWINGS">FIG. 8</figref>, the completed assembly of fuel tank module <b>70</b> on frame rails <b>24</b> and <b>26</b> is illustrated. Fasteners <b>139</b> are installed to attach side rail brackets <b>80</b> and <b>82</b> to frame rails <b>24</b> and <b>26</b> and to attach mounting tabs <b>71</b> and <b>72</b> to side rail brackets <b>80</b> and <b>82</b>. Fasteners <b>139</b> are typically nut and bolt combinations, with the bolts being oriented through the guide arms and mounting tabs so that nuts are attached to the relative outside of the assembly, i.e. from in front of and behind fuel tank module <b>70</b>.

0028Installation of the fuel tank module <b>70</b> on frame rails <b>24</b> and <b>26</b> involves first installing side rail brackets <b>80</b>, <b>82</b> on the frame rails. The sub-assembly of the fuel tank module <b>70</b> is then lowered onto the frame rails, oriented with the mounting tabs <b>71</b>–<b>74</b> downwardly oriented and approximately over their corresponding guide arms. Assuming fuel tank module <b>70</b> is not perfectly aligned, as fuel tank module <b>70</b> is lowered one or more of the mounting tabs encounters either one of the guide arms <b>86</b>–<b>89</b> along a cam section or one of the frame rails <b>24</b>, <b>26</b> against an alignment edge. Contact urges fuel tank module <b>70</b> either to the left or right and either forward or backward to fix the fuel tank module's position. As fuel tank module <b>70</b> becomes fully lowered, its carrier <b>44</b> comes to a rest on support edges <b>97</b> and <b>99</b>, supporting the vertical position of the module. The invention allows assembly of the fuel tank module on the vehicle chassis with a minimum of direct labor input devoted to alignment.

0029While the invention is shown in only one of its forms, it is not thus limited but is susceptible to various changes and modifications without departing from the spirit and scope of the invention.